A cultivated (not necessarily botanical) variety of a plant species or hybrid of two species.
A category in the classification of organisms, ranking below family (Lat. familia) and above species.
A taxon at this rank.
A natural number representing any of several related measures of the complexity of a given manifold or graph.
A group with common attributes.
Within a definition, a broader category of the defined concept.
A type of tuning or intonation, used within an Ancient Greek tetrachord.